Accumulation of Cd and Pb in sediments and Asian swamp eels (Monopterus albus) from downstream area of Cisadane River, Indonesia.

This study examined the presence of two heavy metals (Cd and Pb) in the sediments and Asian swamp eels (Monopterus albus) in the downstream area of Cisadane River. The average concentrations of Cd and Pb in the sediments from all sampling locations were 0.594 ± 0.230 mg/kg and 34.677 ± 24.406 mg/kg, respectively. These concentrations were above the natural background concentration and the recommended value of interim sediment quality guidelines (ISQG), suggesting an enrichment process and potential ecological risk of studied metals to the ecosystem of Cisadane River. The increase in contamination within this region may be attributed to point sources such as landfill areas, as well as the industrial and agricultural land activities in surrounding area, and experienced an increasing level leading towards the estuary of Cisadane River. Meanwhile, the average concentrations of Cd and Pb in the eels from all sampling locations were 0.775 ± 0.528 µg/g and 28.940 ± 12.921 µg/g, respectively. This study also discovered that gill tissues contained higher levels of Cd and Pb than the digestive organ and flesh of Asian swamp eels. These concentrations were higher than Indonesian and international standards, suggesting a potential human health risk and therefore the needs of limitations in the consumption of the eels. Based on the human health risk assessment, the eels from the downstream of Cisadane River are still considered safe to be consumed as long as they comply with the specified maximum consumption limits.

Microplastic contamination in the digestive tract of sea urchins (Echinodermata: Echinoidea) in Kepulauan Seribu, Indonesia.

The accumulation of microplastics on sediment surfaces contributed to the digestive tract of sea urchins contamination during foraging. Therefore, the aim of this study was to investigate the potential relationship between the accumulation of microplastics on sediment surfaces and the contamination of sea urchins' digestive tracts during their foraging activities. Sediment and sea urchins' samples were collected from Pari and Harapan Islands, in Kepulauan Seribu, DKI Jakarta, Indonesia. Microplastics were extracted and observed in sediment and the digestive tract of sea urchins' samples. Fourier transform infrared (FTIR) spectroscopy identified microplastic polymers. The average microplastic concentration on Pari Island was 160 ± 158.75 particles/kg dry weight sediment and 3.93 ± 2.25 particles/g dry weight in the digestive tract of sea urchins. Correspondingly, on Harapan Island, the values were 113 ± 41.63 particles/kg dry weight and 0.27 ± 0.28 particles/g dry weight. Fragment-type microplastics (75%) were predominantly detected in the digestive tract of sea urchins, while fiber-type microplastics (59%) were more common in sediments on Pari Island. Conversely, on Harapan Island fragment types were more prevalent (53%). Microplastics larger than 1000 µm were identified in both sediment and the digestive tract of sea urchins. The observed plastic polymers, such as polyethylene, polyester, and polypropylene were dominant at both study sites. This study postulated that microplastics in sediments may be ingested during sea urchins digestion, supported by a significant correlation of 0.016. Consequently, the presence of microplastics in sea urchins from Pari Island and Harapan Island in Kepulauan Seribu was confirmed. Future investigations should explore the toxic effects of absorbed microplastics on sea urchins' physiology, requiring further analysis.

Microplastic ingestion by the sandfish Holothuria scabra in Lampung and Sumbawa, Indonesia.

This study investigated the abundances and characteristics of microplastics in sediments and sandfish (Holothuria scabra) in Lampung and Sumbawa, Indonesia. Microplastics were found in 89.02% of all sandfish samples, with an average abundance of 2.01 ± 1.59 particles individual-1. The abundance of microplastics was 58.42 ± 24.33 particles kg-1 in surface sediments. Furthermore, there was a positive relationship between the abundance of microplastics in sandfish and sediments. Fragments and fibers with small-sized microplastics (300-1000 µm) were the most abundant types found in sandfish and sediments. Fourier-transform infrared (FTIR) analysis showed that polyethylene (30.08%), polypropylene (30.08%), polyurethane (12.20%), and polyethylene terephthalate (8.94%) were the most abundant polymers in the samples. Our results strongly indicate that microplastics in Lampung and Sumbawa originate from the fragmentation of large plastics. Better solid waste management in Indonesia is needed to reduce plastic waste leakage, which could become microplastics.

The occurrence and abundance of microplastics in surface water of the midstream and downstream of the Cisadane River, Indonesia.

This study investigates microplastic contamination in the midstream to downstream of the Cisadane River and its confluence with the Java Sea. The abundance ranged between 13.33 and 113.33 particles m-3 in surface water samples. Microplastic abundance in the downstream area was higher than midstream. We discovered 11 microplastic polymer types, with polyethylene, polystyrene, and polypropylene dominating (>70%) the chemical composition study result, which we hypothesized was owing to their ubiquitous use in daily household and industrial activities. Microplastic fragments with a diameter of 500-1000 m predominated in surface water samples. This study identifies possible microplastics pollution hotspots throughout the Cisadane rivers and selects sites that require additional sampling. Runoff from cities and landfills has the potential to have a significant impact on the accumulation and movement of microplastics from the inland to the Cisadane estuarine area. Additional research is necessary to determine how and where these microplastics particles enter rivers.

The deposition of atmospheric microplastics in Jakarta-Indonesia: The coastal urban area.

The air pollution in Jakarta has been recorded regularly; meanwhile, the information of atmospheric microplastics is still unknown. This study examines the characteristics (shape, size, and polymer) and deposition rate of atmospheric microplastics in Jakarta. The sample was obtained by putting a rain gauge for 12 months. All microplastic samples were analyzed for polymer using FT-IR. The lowest to the highest percentage of atmospheric microplastic based on shape were foam

Spatio-temporal variation and seasonal dynamics of stranded beach anthropogenic debris on Indonesian beach from the results of nationwide monitoring.

The first stranded macrodebris study on a national scale in Indonesia was conducted on 18 beaches from February 2018 to December 2019. The average weight and abundance of beach debris were higher between October and February (rainy season). The highest stranded macrodebris was located in Ambon, Manado, Takalar, and Padang. Plastic (46.38 %) was the most prevalent type of debris across all macrodebris categories, with single-use plastics such as plastic sachets, plastic bags, and plastic bottles being the dominant macroplastic debris (64.64 %). Based on CCI, HII, and BGI, 18 beaches are "moderately clean," with few hazardous items observed, and "Good." This anthropogenic macrodebris is thought to be more localized (55 %) than transboundary macrodebris. Litter control and environmental quality of this Indonesian coastal region should be improved through a proactive and flexible approach. Finally, extensive stranded beach debris monitoring is recommended to better understand the distribution of macrodebris in the region.

Spatiotemporal macro debris and microplastic variations linked to domestic waste and textile industry in the supercritical Citarum River, Indonesia.

Rivers are the key conduits for land-to-sea debris transport. We present in situ monitoring data of macro debris and microplastic along the supercritical Citarum River in Indonesia We identified the dams as concentrated areas of microplastic. Plastics accounted for 85% of the riverine debris (5369 ± 2320 items or 0.92 ± 0.40 tons daily). We estimated macrodebris releases of 6043 ± 567 items or 1.01 ± 0.19 tons daily with a microplastic concentration of 3.35 ± 0.54 particles per m3 from Citarum River to sea. It has been suggested that population density and urbanization rate are major factors determining the spatiotemporal variability of macrodebris and microplastic abundances in the Citarum River. Our research highlights the importance of long-term monitoring to estimate debris and microplastics inflows along the Indonesian river to the world ocean as a benchmark for the reduction of macro and microdebris into the environment.

The contribution of estuaries to the abundance of microplastics in Jakarta Bay, Indonesia.

Rivers are one of the main pollution routes to the ocean. This study examines the source of microplastics (MPs) in Jakarta Bay based on their characteristics and estimates MPs emissions from 9 estuaries around Jakarta Bay in 3 administrative areas (Tangerang, North Jakarta, and Bekasi). The sample used was the water's surface taken using a round net. The highest abundance was found in the Dadap River, and the lowest was in the Angke River. The characteristics of the MPs are dominated by fragments, the size of 300-500 µm, and composed of polyethylene. It shows that the MPs originate from the fragmentation of residents' plastic waste that has been in the waters for a quite long time. The nine estuaries also showed a high contribution to MPs in Jakarta Bay: from North Jakarta > Tangerang > Bekasi. The emission is highly correlated with water discharge and MPs' particles in each estuary.

Seasonal heterogeneity and a link to precipitation in the release of microplastic during COVID-19 outbreak from the Greater Jakarta area to Jakarta Bay, Indonesia.

To reduce microplastic contamination in the environment, we need to better understand its sources and transit, especially from land to sea. This study examines microplastic contamination in Jakarta's nine river outlets. Microplastics were found in all sampling intervals and areas, ranging from 4.29 to 23.49 particles m-3. The trend of microplastic contamination tends to increase as the anthropogenic activity towards Jakarta Bay from the eastern side of the bay. Our study found a link between rainfall and the abundance of microplastic particles in all river outlets studied. This investigation found polyethylene, polystyrene, and polypropylene in large proportion due to their widespread use in normal daily life and industrial applications. Our research observed an increase in microplastic fibers made of polypropylene over time. We suspect a relationship between COVID-19 PPE waste and microplastic shift in our study area. More research is needed to establish how and where microplastics enter rivers.

Micro- and mesoplastics release from the Indonesian municipal solid waste landfill leachate to the aquatic environment: Case study in Galuga Landfill Area, Indonesia.

Small-sized plastic debris (micro- and mesoplastics) are emerging pollutants and widely detected in aquatic environments. However, micro- and mesoplastics pollution research with regard to landfills is limited. In this study, the occurrence, characteristics, and possible release of micro- and mesoplastic waste from the Galuga landfill leachate to the aquatic environment were studied. Micro- and mesoplastics were identified in all surface water samples from leachate influent and effluent of Galuga landfills. The average daily release to the aquatic environment was estimated at 80,640 ± 604.80 microplastic and 618,240 ± 1905.45 mesoplastic particles, respectively. The amount of microplastic increased three-fold and nine-fold for mesoplastics after input from the leachate drain. Micro- and mesoplastic main chemical compositions were polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyester, and cellophane. This study implied that the leachate may cause micro and mesoplastic contamination to the aquatic environment. The results raised the knowledge of small-sized plastic debris in aquatic environments.

Unprecedented plastic-made personal protective equipment (PPE) debris in river outlets into Jakarta Bay during COVID-19 pandemic.

Increased plastic uses during COVID-19 pandemic challenges efforts to reduce marine plastic debris. Despite recent observations of increased plastic-made personal protection equipment (PPE) waste in coastal areas, comparative data before and during the pandemic lacked. We present in situ monitoring data on riverine debris releases into Jakarta Bay, Indonesia, during COVID-19 pandemic relative to the 2016 baseline data. River debris at two river outlets - the Cilincing and Marunda Rivers, revealed a 5% increase in the abundance of debris and a 23-28% decrease in the weight of debris releases in March-April 2020 compared to March-April 2016, suggesting a compositional shift towards lighter debris. Plastics continued to dominate river debris at 46% (abundance) or 57% (weight). Unique to the pandemic, we observed an unprecedented presence of PPE (medical masks, gloves, hazard suits, face shields, raincoats) that accounted for 15-16% of the collected river debris of 780 ± 138 items (abundance) or 0.13 ± 0.02 tons (weight) daily. The observed increased plastic-made PPE in river outlets urges for improved medical waste management of domestic sources during the prolonged pandemic.

Spatial and temporal distribution of microplastic in surface water of tropical estuary: Case study in Benoa Bay, Bali, Indonesia.

In 2010, Indonesia estimated as the second-largest country in the world that donates plastic to the sea. This study aims to investigate the spatial and temporal distribution of microplastics in tropical estuaries. The sampling was carried out in Benoa Bay with four repetitions representing the wet and dry seasons. Spatially it was found that the highest microplastic abundance around the Suwung landfill, while the lowest at Badung River Estuary, middle, and an inlet of the Benoa Bay. The highest percentage to the lowest microplastic based on the size was 500-1000 µm (37.9%), >1000 µm (35.7%), 300-500 µm (22.1%), and <300 µm (4.3%), while based on the shape were fragments (73.19%), foam (17.02%), fiber (6.38%), and granule (3.40%). No significant differences were found between the wet and dry seasons based on the abundance, but significantly varied based on size and shape. Polymers of microplastics were dominated by polystyrene, polypropylene, and polyethylene.

Stranded marine debris on the touristic beaches in the south of Bali Island, Indonesia: The spatiotemporal abundance and characteristic.

Stranded marine debris (MD) has become a hot topic on Bali Island because it threatens coastal tourism sustainability. This study aims to investigate the spatiotemporal abundance and characteristics of MD on 14 touristic beaches in Bali Island. Sampling is carried out twice every season by adapting methods from NOAA's MD program. We found that the average MD abundance and weight were 0.356 ± 0.366 items/m2 and 4.057 ± 3.892 g/m2, respectively. Plastic dominated the MD based on abundance (86.9%) and weight (40.1%). Plastic bags, straws, and plastic cups are the most common items among plastics. The MD is originated from Indonesia and is dominated by land-based sources. The beaches are categorized as dirty in the rainy seasons and clean in the dry seasons. Statistically, the MD based on abundance, weight, category, source, and level of cleanliness varied significantly between seasons.

Microplastics ingestion by blue panchax fish (Aplocheilus sp.) from Ciliwung Estuary, Jakarta, Indonesia.

Plastic pollution has a detrimental effect on marine environments, and there is limited information regarding its ingestion by biota, which is the primary consumer. Therefore, this research aims to assess microplastic ingestion by blue panchax fish (Aplocheilus sp.). To achieve this, microplastics were extracted and identified from Ciliwung estuary, coastal waters in North Jakarta, and the Aplocheilus sp. Its various forms and sizes were found in river flow (9.37 ± 1.37 particles/m3), coastal waters (8.48 ± 9.43 particles/m3), and in 75% samples of Aplocheilus sp. (1.97 particles/individual). The microplastic size which was of highest concentration in Aplocheilus sp. was relatively small, ranging from 300 to 500 µm. This small size indicates that the fish has difficulty in distinguishing between their food and the microplastics. Further, there was a possibility of the absorption of other pollutants by the plastics. Therefore, an in-depth study on the effects of plastic ingestion on aquatic life, biomagnification, exposure, chemical toxicity, and socio-economy is recommended.

Heavy metal pollution and its relation to the malformation of green mussels cultured in Muara Kamal waters, Jakarta Bay, Indonesia.

Jakarta Bay has become contaminated by both organic and inorganic pollutants, including heavy metals. This study aimed to examine the effect of heavy metal pollution on green mussels cultured in Muara Kamal Waters, Jakarta Bay over seven months. In this research, the water quality was assessed, through measuring the concentrations of the heavy metals, Hg, Pb, Cd, Cr, and Sn in the water, and in the tissue of green mussels that had been cultured there for seven months. The percentage of congenital abnormalities (malformations) in the green mussels was analyzed descriptively and the relationship between the water quality, heavy metals, and green mussel malformation was studied through principal component analysis (PCA). The result showed that the heavy metals concentrations in the water and sediment exceeded the quality standard at Muara Kamal but that in other respects the water quality was quite good. The green mussels cultured there for seven months had accumulated high concentrations of heavy metals, and ±60% of them had malformations of their shells. Based on the heavy metal concentrations in their bodies, the main cause of malformations in green mussels was suspected to be Pb, Hg, and Sn. However, the result of PCA showed it was the interaction between nitrogen compounds, phosphate, turbidity, salinity, pH, as well as the heavy metals in the water that determined the green mussel abnormality.